Hibiscus tea, a tart herbal drink made from the dried calyces of the roselle plant, contains no natural caffeine when prepared without other tea leaves or added ingredients. Research suggests it may help lower blood pressure, although evidence for other health benefits remains limited.
The deep-red beverage, which has a flavour often compared with cranberries, can be served hot or cold. Its naturally caffeine-free composition makes it an alternative to drinks such as coffee and traditional black tea for people seeking to limit caffeine intake.
What research says about hibiscus tea
Hibiscus contains plant compounds, including anthocyanins, that contribute to its colour and antioxidant activity. Researchers have investigated whether these compounds can influence blood pressure, blood glucose and cholesterol levels.
A 2022 systematic review and meta-analysis published in Nutrition Reviews examined 17 clinical trials involving hibiscus preparations. The researchers found that hibiscus was associated with a reduction in systolic blood pressure, although results varied considerably between studies.
The review also found a possible reduction in low-density lipoprotein (LDL), commonly known as bad cholesterol. However, the researchers said further studies were needed to establish the effects of hibiscus on blood glucose and other cardiovascular risk factors.
The US National Center for Complementary and Integrative Health has similarly noted that evidence for hibiscus as a treatment for high blood pressure remains limited. The drink should not replace prescribed medication or other recommended treatment.
Does hibiscus tea affect blood sugar?
Some clinical studies have investigated whether hibiscus can help regulate blood glucose levels, but the findings are inconsistent.
A 2020 systematic review and meta-analysis reported a small reduction in fasting blood glucose across the studies it examined. A separate review published in 2022, however, found no statistically significant effect on fasting blood glucose in its analysis of longer-term trials.
These differences highlight the limitations of the available evidence. Hibiscus tea should not be used as a substitute for diabetes medication, and people managing diabetes should consult a qualified health professional before using concentrated herbal preparations regularly.
Claims that hibiscus tea necessarily damages the liver in people with diabetes are not established by the evidence presented here.
Who should exercise caution?
Although hibiscus tea is commonly consumed as a beverage, its potential effects on blood pressure and blood glucose may be relevant to people taking medication for these conditions.
People using blood-pressure-lowering medicines or medicines that affect blood glucose should seek advice from a health professional before regularly consuming concentrated hibiscus products. Anyone taking prescribed medication should also check for possible interactions rather than assuming that an herbal product is risk-free because it is natural.
Evidence on the long-term safety of high-dose hibiscus preparations remains limited, and findings from extracts or supplements do not necessarily apply to an ordinary cup of tea.
How to prepare hibiscus tea
Hibiscus tea can be prepared using dried roselle calyces and hot water. The calyces are steeped until the drink reaches the desired strength, then strained and served warm or chilled.
Steeping for longer generally produces a stronger, more tart flavour. Honey or another sweetener may be added according to taste, although unsweetened tea avoids the additional sugar.
The beverage can also be served over ice. Its naturally caffeine-free composition makes it suitable for people who want an alternative to caffeinated drinks, provided the product contains no added caffeine-bearing ingredients.
Hibiscus tea is therefore a caffeine-free herbal option with promising, but still developing, evidence for certain cardiovascular benefits. More research is needed to determine the extent of its effects on blood sugar, cholesterol and other aspects of health.
